In this talk, I will show that the axion-nucleon couplings are modified in baryonic matter, as present in neutron stars and supernovae environments. Bounds derived from neutron star cooling and the supernova 1987A get modified. Further, I will show that lighter than expected the QCD axions can get destabilized in sufficiently dense and large objects such as white dwarfs and neutron stars. Once the axion is sourced, the mass of nucleons within the star is reduced, leading to a new ground state of nuclear matter. I will show that white dwarfs in this absolutely stable phase would look very different from what is observed, allowing us to set novel and strong constraints in axion parameter space. Finally, I will show how this new ground state changes the composition of neutron stars.
Hybrid access via ZOOM:
Meeting ID: 984 5733 2925
Peter Thirolf (LMU) / Norbert Kaiser (TUM)